ABSTRACT: Lateralized readiness potentials (LRPs) were used to determine the stage(s) of reaction time (RT) responsible for speed-accuracy trade-offs (SATs). Speeded decisions based on several types of information were examined in 3 experiments, involving, respectively, a line discrimination task, lexical decisions, and an Erikson flanker task. Three levels of SAT were obtained in each experiment by adjusting response deadlines with an adaptive tracking algorithm. Speed stress affected the duration of RT stages both before and after the start of the LRP in all experiments. The latter effect cannot be explained by guessing strategies, by variations in response force, or as an indirect consequence of the pre-LRP effect. Contrary to most models, it suggests that SAT can occur at a late postdecisional stage.
Journal of Experimental Psychology General 07/2004; 133(2):261-82. · 3.99 Impact Factor
ABSTRACT: Romaiguère, Hasbroucq, Possamaï, and Seal (1993) reported a new compatibility effect from a task that required responses of two different target force levels to stimuli of two different intensities. Reaction times were shorter when high and low stimulus intensities were mapped to strong and weak force presses respectively than when this mapping was reversed. We conducted six experiments to refine the interpretation of this effect. Experiments 1 to 4 demonstrated that the compatibility effect is clearly larger for auditory than for visual stimuli. Experiments 5 and 6 generalized this finding to a task where stimulus intensity was irrelevant. This modality difference refines Romaiguère et al.'s (1993) symbolic coding interpretation by showing that modality-specific codes underlie the intensity-force compatibility effect. Possible accounts in terms of differences in the representational mode and action effects are discussed.
The Quarterly Journal of Experimental Psychology A 11/2002; 55(4):1175-91. · 2.45 Impact Factor
ABSTRACT: Previous psychophysical studies have shown that an object, lifted with a precision grip, is perceived as being heavier when
its surface is smooth than when it is rough. Three experiments were conducted to assess whether this surface-weight illusion
increases with object weight, as a simple fusion model suggests. Experiment 1 verified that grip force increases more steeply
with object weight for smooth objects than for rough ones. In Experiment 2, subjects rated the weight of smooth and rough
objects. Smooth objects were judged to be heavier than rough ones; however, this effect did not increase with object weight.
Experiment 3 employed a different psychophysical method and replicated this additive effect, which argues strongly against
the simple fusion model. The whole pattern of results is consistent with a weighted fusion model in which the sensation of
grip force contributes only partially to the perceived heaviness of a lifted object.
Attention Perception & Psychophysics 04/1999; 61(1):23-30. · 2.04 Impact Factor
ABSTRACT: Stelmach, Herdman, and McNeil (1994) suggested recently that the perceived duration for attended stimuli is shorter than that
for unattended ones. In contrast, the attenuation hypothesis (Thomas & Weaver, 1975) suggests the reverse relation between
directed attention and perceived duration. We conducted six experiments to test the validity of the two contradictory hypotheses.
In all the experiments, attention was directed to one of two possible stimulus sources. Experiments 1 and 2 employed stimulus
durations from 70 to 270 msec. A stimulus appeared in either the visual or the auditory modality. Stimuli in the attended
modality were rated as longer than stimuli in the unattended modality. Experiment 3 replicated this finding using a different
psychophysical procedure. Experiments 4-6 showed that the finding applies not only to stimuli from different sensory modalities
but also to stimuli appearing at different locations within the visual field. The results of all six experiments support the
assumption that directed attention prolongs the perceived duration of a stimulus.
Attention Perception & Psychophysics 04/1998; 60(8):1305-1317. · 2.04 Impact Factor
ABSTRACT: Three experiments examined whether temporal uncertainty about the delivery of a response stimulus affects response force in
a simple reaction time (RT) situation. All experiments manipulated the foreperiod; that is, the interval between a warning
signal and the response stimulus. In the constant condition, foreperiod length was kept constant over a block of trials but
changed from block to block. In the variable condition, foreperiod length varied randomly from trial to trial. A visual warning
and response stimulus were used in Experiment 1; response force decreased with foreperiod length in the variable condition,
but increased in the constant condition. This result is consistent with the hypothesis that responses are less forceful when
the temporal occurrence of the response stimulus is predictable. In a second experiment with an auditory warning signal and
a response stimulus, response force was less sensitive to foreperiod manipulations. The third experiment manipulated both
the modality and the intensity of the response signal and employed a tactile warning signal. This experiment indicated that
neither the modality nor the intensity of the response signal affects the relation between response force and foreperiod length.
An extension of Näätänen’s (1971) motor-readiness model accounts for the main results.
Attention Perception & Psychophysics 04/1997; 59(7):1089-1097. · 2.04 Impact Factor
ABSTRACT: In order to assess Donders’s assumption of pure insertion for the response execution stage, we measured the magnitude and time course of response force in the three classical reaction time (RT) tasks: simple RT, go/nogo and choice RT. Response force was virtually identical for the simple and choice RT tasks (Experiments 1 and 2). However, the go/nogo task yielded more forceful responses than both the simple RT (Experiment 3) and choice RT (Experiments 4 and 5) tasks. These results support Donders’s original assumption that the response execution process operates identically in the simple and choice RT tasks. More response activation seems to be generated in the go/nogo task, however, consistent with a motor readiness model.